140
P. Wei, D.A. Atwood / Journal of Molecular Structure 478 (1999) 139–143
Table 1
positions. The ammonium hydrogens were originally
found from the difference Fourier maps and then put
into positions fixed to the attached nitrogen. Absorp-
tion corrections were not employed. Further details of
the structure analysis are given in Table 1. Positional
parameters and selected bond lengths and angles are
presented in Tables 2 and 3, respectively.
Data collection and processing parameters for compound (1)
Compounds
Formula
1
C19H31NO4F3SNd0.33
474.59
pale blue prism
Formula weight
Colour, habit
Crystal size (mm3)
Crystal system
Space group
0.50 × 0.25 × 0.20
Trigonal
R-3
˚
a (A)
18.372(1)
83.359(4)
90
120
24369(2)
36
8892
1.164
0.784
^ h, ^ k, ^ l; 45Њ
1869
1834 [F Ն 4s(F)]
˚
c (A)
4. Results and discussion
a (Њ)
g (Њ)
V (A )
As part of a program to prepare molecular precur-
sors to mixed-metal oxide solid-state materials the
combination of various aluminates with Nd(OTf)3
was examined. The goal was to prepare mixed-metal
derivatives supported by a range of bidentate amino-
phenoxide ligands (Scheme 1a). Unfortunately, these
reactions have led, up to the present, to ill-defined
products. In only one instance was a well-character-
ized product obtained (Scheme 1b). This product
(compound 1) is apparently the result of addition of
adventitious water to the reaction mixture. It should
be noted, however, that it is often difficult to prevent
water from adding to a reaction containing lanthanide
reagents even under inert conditions. For example,
this can be observed in the formation of
Ln5(OiPr)13(m5-O) in aged samples of Ln(OiPr)3 (Ln
Yb [8], La, Y) [9].
3
˚
Z
F(000)
D(calcd) (g cmϪ3
)
m(mmϪ1
)
Collection range; 2umax
Unique data measured
Observed data, n
No. of variables, p
R1
253
0.053
0.136
1.27
wR2
S (goodness of fit)
0.89 mmol) in thf (20 ml). The resulting mixture was
stirred for 6 h at room temperature. After filtration and
concentration, pale blue crystals were grown at
Ϫ30ЊC (0.45 g, 37%). Mp 186ЊC (dec); 1H NMR
(270 MHz, d6-DMSO): d 1.04 (d, 6H, CHCH3), 1.21
(s, 9H, CCH3), 1.33 (s, 9H, CCH3), 2.74 (m, 1H,
NCH), 3.83 (s, 2H, PhCH2), 6.87 (d, 1H, PhH), 7.05
(d, 1H, PhH).
1
Compound (1) is soluble in thf and dmso. A H
NMR spectrum of (1) in the latter solvent demon-
strates that the solution structure contains equivalent
environments for the three ligands. Based upon the
fact that the nitrogens are protonated, it is likely that
the triflate groups remain coordinated in solution and
that the ligands remain monodentate.
3. Structure determination
X-ray Data for 1 was collected on a Siemens
SMART-CCD unit with Moka radiation. The posi-
tion of the Nd atom was determined with a Patterson
function. Subsequently, the structure was refined
using the Siemens software package SHELXTL 4.0.
All of the non-hydrogen atoms were refined anisotro-
The equivalence of the three ligands and three
triflate groups are evident in the crystal structure of
(1). In the structure there is a three-fold axis of
symmetry passing through the Nd atom. It is coordi-
nated by six oxygen atoms in a trigonally distorted
octahedral arrangement, three from the ligand and
three from the triflates. It is interesting to note that
the ligands are grouped so that all three of each occu-
pies one triangular face. By comparison, the structure
of [La(OTf)3(thf)(tetraethyleneglycol)], contains OTf
groups that are evenly distributed about the central
metal [6]. The unusual ligand arrangement in (1)
can be attributed to intramolecular hydrogen bonding
t
pically with the exception of three of the ligand Bu
groups. These were disordered and modeled by
dividing the occupancy for each atom across two
atom positions. This provided a symmetric model
consisting of six atoms having half-occupancy each.
Except for the disordered carbons and the ammonium
hydrogen, hydrogens were put into calculated
Wei, Pingrong
